package niu;

import java.util.Scanner;

public class ke {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String sc = scanner.nextLine();
        StringBuilder sb=new StringBuilder(sc);
        for(int i=0;i<sc.length();i++){
            for(int j=i+1;j<sc.length();j++){
                if(sb.charAt(i)==sb.charAt(j)){
                    sb.deleteCharAt(j);
                }
            }
        }
        System.out.println(sb);
    }
}



